The present invention relates to a coupling for a multi-passage tube, and more particularly to a coupling capable of easily connecting a multi-passage tube having a plurality of fluid passages for introducing and discharging a fluid to a pneumatic device such as a solenoid-operated valve, a cylinder, or the like.
Fluid-pressure-operated devices are heretofore in widespread use for utilizing a fluid such as air to drive and control objects. Such fluid-pressure-operated devices normally have a plurality of ports for introducing and discharging the fluid, and tubes are connected to these ports. These tubes for introducing and discharging the fluid are designed in as compact an arrangement as possible for reducing the space for installation thereof to facilitate their maintenance and servicing. One example of such a tubing arrangment is illustrated in FIG. 1 of the accompanying drawings.
A device 2 such as the manifold of a solenoid-operated valve has first and second ports 4, 6 to which tubes 8,10 are connected respectively. A first tube coupling 12 is interposed between the tube 8 and the first port 4, and a second tube coupling 14 is interposed between the tube 10 and the second port 6. Actually, the first and second couplings 12, 14 have ends threaded respectively in the first and second ports 4, 6, and the tubes 8, 10 are fitted respectively over engagement tubes 16, 18 integral with the first and second tube couplings 12, 14, respectively.
The tubes 8, 10 are put together by a string 20, a band or the like to reduce their installation space and make their maintenance and servicing easy. With the illustrated conventional arrangement, however, the number of tubes such as the tubes 8, 10 is increased if the fluid-pressure-operated device has many ports as with a manifold-type solenoid-operated valve. As the number of tubes used is larger, the tubing system required becomes more complex, and the space taken up by the tubing system also becomes greater. Furthermore, since the tubes required to be held together by the string 20, a band or the like at several locations therealong, a certain number of fastening steps are required to bundle the tubes together. The more the tubes are employed, the more steps are required to arrange the tubes, with the result that the danger of connecting some tubes to wrong ports will be increased. In addition, when a plurality of tubes are tied by a string, a band or the like, the pitches or distances between the tubes are reduced. Due to the reduced pitches, it would be difficult for the operator to insert the tubes into the respective tube couplings for connection to the device. The increased number of tube couplings used also tends to result in an increase in the number of steps of arranging the tubes in place.